This program-project investigation, now in its fourth year, combines clinical studies of patients in long-term outpatient follow-up and selected inpatients for observation with laboratory techniques designed to yield information in the following areas: Immunology, Virology, Neuropathology and Electronmicroscopy, Blood-brain-barrier Physiology, Myelinotoxicity in Multiple Sclerosis CSF and Brain, Immunoglobulins, Clinical Electrophysiology (based on evoked potentials). The objectives are to gain basic and clinical information pertinent to the clinical course, etiology, pathogenesis of symptoms, pathophysiology, immunologic mechanisms and neurochemical data as means to provide logical approaches to the understanding and treatment of multiple sclerosis. To further the objectives and to gain the benefits of a diverse scientific team for possible prompt application, a tight organization of the group is maintained.